Turbine blade model grinder



April 9, 1957 Filed March 4, 1954 H. E. BALSIGER TURBINE BLADE MODEL GRINDER 3 Sheets-Sheet l INVENTOR #400: 5.841.965)? ATTORNEY April 9, 1957 H. E. BALSIGER TURBINE BLADE MODEL GRINDER Filed March 4, 19 54 5 Sheets-Sheet 2.

R R Y O I E wm m W n April 9, 1957 H. E. BALSIGER 2,787,870

TURBINE BLADE MODEL GRINDER Filed March 4, 195

3 Sheets-Sheet 5 k 3 Q o a X s N J q s o 5 5'1 1 I INVENTOR ATTORNEY 2,787,870 TURBINE BLADE MODEL GRINDER Harold E. Balsiger, Waynesboro, Pa., assignor to Landis Tool Company, Waynesboro, Pa.

Application March 4, 1954, Serial No. 414,209

13 Claims. (Cl. 51-101) This invention relates to apparatus for copy grinding work pieces of non-cylindrical contour in which the grinding or other tool is actuated by a pattern or master to produce the desired contour on the workpiece.

The usual method of grinding rotatable non-cylindrical work pieces is to mount the work on a cradle along with a pattern which rotates in engagement with a follower to rock the cradle which rotates toward and away from a grinding wheel. The pattern and follower are usually held in engagement by a spring which is strong enough to insure constant engagement between the parts during rotation. The construction of pattern or master cam is usually sufliciently rigid that the force exerted by the spring is not enough to cause any deflection.

Where the pattern is a turbine blade or other'article of .relatively light construction, the force of such a spring holding the pattern against a follower would cause considerable strain on the pattern with resultant inaccuracy in the model being ground.

It is an object of this invention to provide a machine wherein the work pieceand pattern are mounted in the same relation as in conventional cam grinding, but the pattern controls the movement of the wheel rather than the work.

A further object is to provide a simple form of control for the wheel support actuating loader which will be of maximum sensitivity to the contour of the pattern.

A further object is to provide the hydraulic system in which the volume of flow remains constant regardless of changes in pressure, viscosity, load or valve opening.

A further object is to provide means whereby a constant pressure is exerted on one end of the wheel motor and an adjustable pressure at the opposite end of said motor.

A further object is to provide a servo mechanism in which the control member acts to control the fiow of fluid whereby to increase or decrease the pressure on either side of the motor for any given position of the pattern follower.

Figure 1 is a plan view.

Figure 2 is an end elevation of the wheel support including an electric and hydraulic diagram showing the controls for operating said wheel support.

Figure 3 is a hydraulic diagram showing the means for providing longitudinal movement between the wheel and work.

Numeral indicates the bed of a grinding machine, Ila work support slidably mounted for movement longi' tudinally thereof, and 12 is a grinding wheel support slidably mounted for movement transversely of said bed.

Themeans for effecting said transverse movement consists of a cylinder 20 on bed 10 and having a piston 21 slidably mounted therein. Piston rod 22 is connected to arm 23 which in turn is attached to wheel support 12. Fluidunder pressure is supplied to the left end of said cylinder by pump 30 through line 31, valve 33 and line 34. Fluid under pressure is supplied to the right end of cylinder 20 by pump 40 through line 41 to valve 42 States Patent and line 43. However, the preferred arrangement is to supply fluid direct from line 41 through line and line 43 to cylinder 20. Valves 33 and 42 are so constructed that the fluid directed thereto through lines 31 and 41 respectively is divided in a predetermined proportion between the lines 34 and 43 leading to cylinder 20, and lines 35 and 46, leading to opposed nozzles 36 and 47 respectively. Equal pressures are maintained in said lines by the balancing elements 37 and 43 in said valves. Structure of valves 33 and 42 are shown and described in greater detail in application 5. N. 487,288, filed February 10, 1955. Said nozzles are mounted on a bracket which in turn is slidably mounted on bracket 51. Said bracket 51 is mounted in fixed position on wheel base 12. Between said opposed nozzles is a valve member 55 movable in a horizontal direction to regulate the flow of fluid from said nozzles. Said valve member is mounted on a block 56 which in turn is connected through parallel leaf springs 57 on a portion 58 of sliding bracket 50. Mounted for vertical adjustment on block 56 is a follower shoe 60 having a curved surface 61 substantially of the same radius as grinding wheel 13 and yieldingly engaging a rotatable non-cylindrical pattern member 62.

Indicator 65 is mounted in an arm 66 on bracket 51. A stop 67 on valve 55 engages the stem of indicator 65 to show variation in movement between the wheel base 12 and the follower 6d. The position of bracket 50 on slide 51 may be adjusted by means of a screw 70 having knurled handle 71. One end of said screw is secured to a lug 72 on slidable bracket 50. The threaded portion of said screw is mounted in a threaded member 73 which in turn is fixedly mounted on bracket 51. A spring '74 serves to take up backlash between lug 72 and threaded member 73-.

An indicator '75 is mounted on an arm 76 on bracket 51. The feeler of said indicator engages any suitable surface movable with bracket 50 to Show the extent of movement of said wheel support 12.

illustration, a hydraulic system shown diagrammatically in Figure 3 is used. Said system consists of a cylinder iliiiin bed 10. A piston 101 slidable insaid cylinderis connected through piston rod 102 and bracket 163 to carriage 11. Fluid under pressure is directed to said cylinder from a pump 165 to line 106 having astart and stop valve 107 actuated in one direction bya spring 108 and in the opposite direction by solenoid 109. From said start and stop valve, line lltlhaving a throttle valve Jill therein, conducts fluid under pressure to reversing valve 112 from which said fluid may be directed to opposite ends of cylinder ltitl through lines 113 and 134. Reversing valve 112 may be positioned by a lever 115. A dog 12% on work drive shaft 121 serves to actuate a limit switch 122 on carriage 11. Each time the work com pletes one revolution said switch connectssolenoid 1439 through lines 125 and .126 with current supply L1. L2 is connected to saidsolenoid through line 127. A measured amount of fluid under pressure .will be directed to said reversing valve and cylinder 106 to move carriage it enough to move another increment of the work piece into engagement with the grinding wheel.

Operation A description of the operation of the invention will be limited to the preferred form thereof. As indicated above, this form consists in connecting pump as directly to the right end of cylinder 20 through line 45 thus proaccomplished by adjusting the pressure in line 34 above and below the constant pressure in line 45 by movement of valve 55 relative to nozzle 36 in response to the rotation of pattern 62 to eflect a predetermined controlled reciprocating movement of piston 21 and grinding wheel I V 13 in engagement with workpiece 80. The blank work piece 80 and a model 62 are rotatably mounted in the machine as described above. The work is rotated by a suitable headstock 82, details of which are not shown. Pump is started by any suitable means. Fluid under pressure is directed therefrom through line 31 to valve 33 in which the fluid is divided by restrictions 38 and 39 of different sizes. One portion of said fluid is discharged from said valve through line 34 to the rod end of cylinder 20 to hold or move piston 21 and hence Wheel base 12 in retracted position. The other portion of said fluid is discharged from said valve through line 35 and nozzle 36. The portion directed to cylinder 20 is further divided, in that, a variable portion thereof is discharged through valve 33 depending upon the condition under which cylinder 20 is functioning. If piston 21 is not moving, all of the fluid passing through restriction 39 will be discharged through line 32. The pressure in line 35 will vary inversely as the distance between valve 55 and nozzle 36. As the space between said valve and said nozzle increases, the pressure in line 34 decreases under the control of valve 33. This'is practically a straight line variation. The pressure in line 34 and the left end of the cylinder 20 will vary directly as the pressure in line 35 since valve 33 keeps both pressures equal, although both may increase or decrease. The flow of fluid pasing through nozzle 36 is constant and thus, it is not affected by changes in temperature, load, and etc. For any given change in the position of valve member 55, the change in pressure in lines 34 and 35 and the left end of cylinder 20 will be the same. It is only by keeping the flow from nozzle 36 constant that it is possible for piston 21 to move the tool support exactly in accordance with the contour of pattern 62. The pressure in line 35 is dependent upon the distance of the valve member 55 from nozzle 36. The discharge from nozzle 36 is constant regardless of its relation to member 55 or other variable factors such as temperature, load and so forth. The constant flow at nozzle 36 is essential since it is the only way to provide a true reflection of the contour of the pattern transmitted through the fluid connection in the form of a corresponding variation in pressure on one side of the cylinder 20 relative to the fixed pressure in the opposite side of said cylinder. The jet of fluid emerging from nozzle 36 is in effect, similar to a mechanical lever. A change in the rate of flow would be equivalent to a change in the ratio of the lever arm with a corresponding change in effect on the movement of the cutting tool toward and from the workpiece.

Pressure in line 34 acts on pressure switch 150 to close a circuit from L2 through lines 151 and 152 to the motor for driving pump 40. There is a direct connection from L1 through line 153 to said motor which is shown. Pump 40 thereupon directs fluid through line 41 and line 45 to the head end of cylinder 20. The direction of movement of piston 21 and therefore wheel base 12 and grinding wheel 13 will be determined by changes in pressure in line 34. Such changes in pressure will be effected by movement of valve to change the rate of discharge of fluid from nozzle 36 in response to rotaing for the flow of fluid therefrom, the pressure increase in line 35 is reflected through valve 33 and line 34 to the rod end of cylinder 20. Piston 21 is moved to the right to position grinding wheel 13 for grinding that portion of the work piece corresponding angularly to the portion of the model 62 in engagement with shoe 61. As said model rotates, shoe 61 and valve 55 may move to the left in following the contour of said model, thus increasing the space between valve 55 and nozzle 36 and reducing the pressure in line 35 and the left end of cylinder 20 to a point less than the pressure in the right end of cylinder 20 whereupon piston 21 will move to the left to position wheel 13 for grinding another portion of work piece 80 corresponding to that portion of model 62 then in engagement with follower 61. Since there is no reversing valve for directing fluid alternately to opposite ends of cylinder 20, the means for changing direction of movement of piston 21 is dependent only on the change in pressure in line 35 and this is reflected immediately at the rod end of cylinder 20, thus eliminating delay incidental to the operation of a reversing valve.

The function of valve 42 is reflecting the variation in discharge from nozzle 47 on the pressure in line 43 just as valve 33 reflects the variation in discharge from nozzle 36 on the pressure in line 34. Thus, as piston 62 actuates valve member 55, the discharges from nozzles 36 and 47 are restricted alternately in accordance with the contour of said pattern 62 and with consequent reciprocation of piston 21 and grinding wheel 13 relative to workpiece 80.

Attached to headstock spindle 121 and rotatable therewith is a dog which serves to actuate limit switch 122 once for each revolution of the work 13. Said limit switch completes circuit from L1 through lines 126 and to solenoid 109 which is connected through line 127 to L2. Solenoid 109 shifts valve 107 against spring 108 to connect pump 105 through line 106 to line 110, throttle valve 111 and reversing valve 112, which is set to conduct fluid under pressure through line 113 to the head end of traverse cylinder 100 to move piston 101 which is connected through piston rod 102 and bracket 103 to work carriage 11. The energization of solenoid 109 is momentary so that only a small amount of fluid is directed to cylinder 100, suflicient to move carriage 11 and place the next increment of work piece 80 in engagement with grinding wheel 13.

I claim:

1. A machine for grinding non-cylindrical work pieces comprising a base, a work support slidably mounted on said base and having means for rotatably supporting a workpiece thereon, a grinding wheel slide mounted on said base for movement toward and from operative position relative to a work piece, a grinding wheel rotatably mounted on said slide, means for eflecting said movement comprising a piston and cylinder, one of which is attached to said slide, a source of fluid under pressure connected directly to one end of said cylinder, means for controlling the movement of said wheel slide in accordance with the shape of the piece to be ground compris ing a pattern mounted in alignment with the axis of said rotatable work supporting means for alignment with the axis of said work piece and rotatable therewith, a follower resiliently mounted for movement with said wheel .slide and having a valve member attached thereto. .a nozzle in said fluid connection mounted for adjustment relative to said follower and having a restricted opening for discharging a jet of fluid against said valve member, a connection between said nozzle and the other end of said cylinder and a second supply of fluid under pressure connected to said line.

2. A machine for grinding non-cylindrical work pieces 2 comprising a base, a work support slidably mounted on said base and. having means for rotatably supporting a work piece thereon, a grinding wheel slide mounted on said base for movement toward and from operative posieastern tionrelative to said work support, agrinding wheel rotatably mounted on said s1ide,,meansfor eflecting said. movement comprising a piston and cylinder, one .of which is attached to said slide, a source of fluid under pressure connected directly to one end of said cylinder, :means for controlling movement of said wheel slide in accordance with the shape of the piece to be ground, comprising a pattern mounted in alignment with the axis of said rotatable work supporting means for alignment with the axis of said work piece and rotatable therewith, a follower resiliently mounted on said wheel slide for yieldingly engaging said pattern, a supply of fluid under pressure connected to the other end of said cylinder, a nozzle in said fluid connection mounted in .fixed relation to said follower and having a restricted opening for directing a jet of fluid against a portion of vsaid follower, said follower being responsive to rotation of said pattern to vary the space between said opening and;said portion of said follower and thus vary the pressure at one end of said cylinder above or below the pressure at the other end of said cylinder.

3. A machine for grinding work pieces which an irregular in shape comprisinga base, a work support slidably mounted on said base and having means for vrotatably supporting a workpiece thereon, a grinding wheel slide mounted on said base for movement toward and from operative position relative to a work piece, a grinding wheel rotatably mounted on said slide,- means for effecting said movement comprising a piston and cylinder, one of which is attached to said slide, a source of fluid under pressure connected directly to one end of said cylinder, means for controlling the movement of said wheel slide in accordance with the shape of the piece to be ground comprising a pattern rotatable therewith, a follower resiliently mounted for movement with said wheel slide, a nozzle mounted for adjustment relative to said follower and having a restricted opening fordirecting a jet of fluid against a portion of said follower, said connection comprising a valve having means for dividing the fluid supplied thereto into predetermined portions, one of which is directed to said nozzle, the other to the other end of said cylinder 4. In a machine of the kind described, a hydraulic motor for moving an element of said machine alternately in opposite directions comprising a piston and cylinder, at source of fluid under pressure connected to one end of said cylinder, a source of fluid under pressure connected to the other end of said cylinder to actuate said motor in opposite directions comprising a by-pass in one of said connections, means for varying the opening of said by-pass comprising a pattern movable in unison with a work piece and means actuated thereby to change the balance of fluid pressure at opposite ends of said cylinder and means in said connection for maintaining a constant volume flow of fluid therethrough.

5. In a machine tool, an element movable in opposite directions, means for effecting said movement comprising a piston and cylinder, one of which is connected to said element, a motor driven pump connected to supply fluid under pressure to one end of said cylinder, at second motor driven pump having connections to the other end of said cylinder, a pressure switch in the circuit to said second motor driven pump, said pressure switch being connected to the pressure line from said first mentioned pump whereby said second pump cannot function to supply fiuid for moving said motor in one direction until a predetermined pressure has been built up in the line connecting said first mentioned pump with the opposite end or" said motor.

6. In a machine tool, an element movable in opposite directions, means for eflecting said movement comprising a piston and cylinder, one of which is connected to said element, a motor driven pump connected to supply fluid under pressure to one end of said cylinder to move said element away from an operative position, a second .motor driven pump having connections to the other end ofsaid cylinder, a pressure operated control means in the circuit to said second motor driven pump, said control means being connected to the pressure line from said first mentioned pump whereby said second pump cannot function to supply fluid for moving said element toward an operative position until a predetermined pressure has been built up in the line supplying fluid to said motor to holdsaid element in inoperative position.

7. In a machine tool, a bed, a work support rotatably mounted thereon, a tool support slidably mounted thereon, means .for eflecting relative transverse and longitudinal movement of said supports including a motor connected to each of said supports, one of said motors-comprising a piston and cylinder, means for rotatably supporting a work piece ,on said work support, a pattern member rotatable with said work piece, a separate supply of fluid to each end of said cylinder for effecting said transverse movement and means actuated by rotation of said pattern for controlling the supply of fluid to one end of said cylinder to eflect a reciprocating movement of one of said supportsrelative to the other in a manner dependent upon the shape of said pattern.

8. Ina machine tool, a bed, a work support rotatably mounted thereon, a tool support slidably mounted thereon, means for effecting relative transverse and longitudinal movement of said supports including a motor connected to each of said supports, one of said motors comprising a piston and cylinder, means for rotatably supporting a work piece on said work support, a pattern member rotatable with said work piece, a separate supply of fluid to each end of said cylinder for eflecting said transverse movement and means including a by-pass actuated by rotation of said pattern for controlling the supply of fluid to one end of said cylinder to effect a reciprocat ing movement of one of said Supports relative to the other in a manner dependent upon the shape of said pattern.

9. In a machine tool, a bed, a work support slidably mounted .thereoma tool support slidably mounted thereon, means for effecting relative transverse and longitudinal movements of said supports including a motor connected to each of said supports, one of said motors comprising a piston and cylinder, means for rotatably supporting a work piece on said work support, means for rotating said work piece, a pattern member rotatable with said work piece, a separate supply of fluid to each end of said cylinder for effecting said transverse movement and means actuated by said pattern for controlling the supply of fluid to one end of said cylinder to effect a reciprocating movement of one of said supports in a manner dependent upon the shape of said pattern and means actuated by said work rotating means for effecting incremental operation of said longitudinal moving motor.

10. In a machine tool, a bed, a work support rotatabiy mounted thereon, a tool support slidably mounted thereon, means for effecting relative transverse and longitudinal movements of said supports including a motor connected to each of said supports, one of said motors comprising a piston and cylinder, means for rotatably supporting a work piece on said work support, a pattern member rotatable with said work piece, a separate supply of fluid to each end of said cylinder for eflecting said transverse movement and means actuated by said pattern for controlling the supply of fluid to one end of said cylinder to eflect a reciprocating movement of one of said supports in a manner dependent upon the shape of said pattern and means to effect said longitudinal movement by predetermined increments.

11. A machine for grinding workpieces which are irregular in shape comprising a base, a work support slidably mounted on said base and having means for rotatably supporting a workpiece thereon, a grinding wheel slide mounted on said base for movement toward and from operative position relative to a workpiece, a grinding wheel rotatably mounted on said slide, means for eifecting said movement comprising a piston and cylinder, one of which is attached to said slide, a source of fluid under pressure connected directly to one end of said cylinder, means for controlling the movement of said wheel slide in accordance with the shape of the piece to be ground comprising a pattern rotatable therewith, a follower resiliently mounted for movement with said wheel slide, a nozzle mounted for adjustment relative to said follower and having a restricted opening for directing a jet of fluid against a portion of said follower, said connection comprising a valve having means for dividing the fluid supplied thereto into predetermined portions, one of which is directed to said nozzle at a fixed rate, the other of which is directed to the other end of said cylinder and means for maintaining equal pressures in both of said portions.

12. A machine for grinding non-cylindrical workpieces comprising a base, a work support slidably mounted on said base and having means for rotatably supporting a workpiece thereon, a grinding wheel slide mounted on said base for movement toward and from operative position relative to said work support, a grinding wheel rotatably mounted on said slide, means for effecting said transverse movement comprising a piston and cylinder, one of which is attached to said slide, a separate source of fluid under pressure connected to each end of said cylinder, means for controlling movement of said wheel.

slide in accordance with the shape of the piece to be ground comprising a pattern mounted in alignment with the axis of said rotatable work supporting means for alignment with the axis of said workpiece and rotatable therewith, a follower resiliently mounted on said wheel slide for yieldingly engaging said pattern, a nozzle for discharging a part of the fluid supplied to one end of said cylinder, a valve member connected to said follower in position to obstruct the discharge of fluid from said nozzle and a valve responsive to change in pressure in said nozzle to effect a corresponding change in pressure in one end of said cylinder whereby to shift said wheel 8 slide and wheel toward and from a workpiece in accordance with the contour of said pattern.

13. A machine for'grinding workpieces which are irregular in shape comprising a base, a work support slidably mounted on said base and having means for rotatably supporting a workpiece thereon, a grinding wheel slide mounted on said base for movement toward andfrom operative position relative to a workpiece, a grinding wheel rotatably mounted on said slide, means for effecting said movement comprising a piston and cylinder, one of which is attached to said slide, a source of fluid under pressure connected directly to one end of said cylinder, means for controlling the movement of said wheel slide in accordance with the shape of the piece to be ground comprising a pattern rotatable therewith, a follower resiliently mounted for movement with said wheel slide, a nozzle mounted for adjustment relative to said follower and having a restricted opening for directing a jet of fluid against a portion of said follower, said connection comprising a valve having means for dividing the fluid supplied thereto into predetermined portions, means in said valve for directing one of said portions to said nozzle at a fixed rate and means in said valve for directing the other portion to the other end of said cylinder at a pressure which varies directly with the pressure at said nozzle.

References Cited in the tile of this patent UNITED STATES PATENTS 

